Air venting apparatus



Dec. 17, 1940. A. D. ROSE Em 2.224,929

AIR VENTING APPARATUS Filed March 16, 1938 5 sheezs-sheet 1 Dec; 17,1940.

Filed March .16, 1938 A. D. ROSE ET AL AIR VENTING APPARATUS C'rSheets-Sheet 2 Dec. 17, 1940. A. D. ROSE ETAL AIR VENTING' APPARATUSFiled March 16, 1938 3 Sheets-Sheet 3 Illlllfrrlz Patented Dec. 17, 1940UNITED s'rATE-s- P'Arl-:NT oFFic cago, Ill.,

assignors to Jas. P. March Corporation, Chicago, Ill., a corporation ofIllinois Application March 16, 1938, Serial No. 196,170

22 Claims.

Our invention relates to air-venting apparatus for air-bound containers.More specifically', it relates to air-venting apparatus for radiator-sused in a hot water heating system of the socalled closed type.

The trend in hot water heating systems is toward the use of theso-called 'fclosed",systems as against the so-called.open" expansiontank systems, operating under atmospheric pressures that have been usedin the past. The closed systems Operating under higher pressures havethe advantage of enabling the use of higher `tempera- "wturef water andpromoting more rapid circulation of water, two factors that aid insecuring economy of operation and more heating comfort;

The use of circulating pumps is becoming` general in order to stillfurther speed up circulation. The use of circulating pumps and higherOperating pressures has also had the effect of permi'tting the use ofsmaller pipe and fittings and thus materially reducing the cost ofinstallation.

In the so-called "closed systems the water naturally expands as it isheated and the surplus volume must be removed from the heating system.The removal of this water is accomplished by means of spring loadedpressure valves. Other spring loaded pressure valves act to replace thisvolume ofwater when the water temperature and pressure is lowered. Thusfresh water is continually being injected into the system. This freshwater from the city mains carries an appreciable amount of entrained airand this air has a tendency to collect in the individual radiators. Theradiators become air-bound, the circulation of water may be impeded, andradiating capacity is reduced. It is of great importance. therefore,that the individual radiators frequently be vented so as to prevent airaccumulation.

The conventional type of radiator air valve used on steam or vaporsystems is not suitable for this operation, due to the danger that thefloat needle may not seat properly and the relatively high waterpressure would cause disastrous leakage and flooding with great damageto the building structure and furnishings. As a result,V

the venting of hot water radiators is now done manually, each radiatorbeing individually vented.

The venting of radiators, while being a simple operation, is being mademore difficult by the use of concealed radiation. It is one of the hometasks that is usually neglected, much to the detriment of the homeheating operation.

One of the objects of our invention is to'pro- (Cl. 237-56) l vide animproved air-venting apparatus that enables one to vent all of theradiators in a system simultaneously, either by manual, automatic, orSemi-automatic means.

- A further object of our invention is to provide 5 apparatus of thetype indicated above in which the venting operation is accomplished byopening one or more centrally-located control valves. A further objectof our invention is to provide an apparatus of the type indicated abovein 10 which the individual vent valves are tightly closed by therelatively great Operating pressure of the water: in the system. thusprecluding the danger of accidental fiooding.

A further object of our invention is to'provide 15 apparatus of the typeindicated in which radiators in the same system on different levels maybe vented from a central control station. w

A further object of our invention is to provide such a construction inwhich a valve controlled 20 by the liquid level in the radiator` acts asa relay valve. t I

Further objects and advantages of the invention will be apparent fromthe description and claims.

In the drawings, in which several forms of our invention are shown,

Figure l is a view, partly in perspetive and partly in elevation,showing a hot water heating system in which our improved apparatus isused; 30

Fig. 2 is a Vertical, axial section of the control valve apparatus usedin Fig. 1;

Fig. 3 is an elevational view of the apparatus shown in Fig. 2;

, Fig. 4 is a Vertical, axial, sectional view show- 35 ing a vent valveapparatus in which the venting is accomplished by a decrease of pressurein one position it assumes;

Fig. 5 is a view of the apparatus of Fig. 4 in a different position;

Fig. 6 is a view of theapparatus of Fig. 4 showing still anotherposition;v

Fig. 7 is a view of the apparatus of Fig. 4 showing still anotherposition;

Fig. 8 is a. perspective view showing a somewhat 45 differentarrangement of control for -the supply of water to the heating system;

Fig. 9 is a Vertical, axial, sectional view of the control valvemechanism used inFig. 8;

Fig. 10 is an axial sectional view showing an 50 air vent controlmechanism suitable for use where the venting is effected by an increaseof pressure above the normal range in a system;

Pig. 11 is agdiagrammatic view showing automatic control means; and 55Fig. 12 is a diagrammatic control valve in combination tank.

Referring to the drawings in detail and first to Figs. 1 to 7,inclusive, the construction shown in Fig. 1 comprises a hot water heaterI, a plurality of radiators 2 located on different floors, supply pipes3 for supplying hot water to the radiators, return pipes 4 for thereturn of the water from the radiators to the heater I, means 5 forcontrolling the supply of water to the system and the pressure of thewater in the system, and means 6 Controlled by the water level in theindividual radiators andby the pressure of the water in the radiatorsfor controlling the venting of air from air-bound radiators.

As indicated above, in hot water heating systems of the closed typeshown, means are usually provided which will in general maintain thepressure in the system between upper and lower limits. Thus, apressure-regulating valve 'i is provided which in general will causeadditional water to be supplied to the system if the pressure in thesystem drops below a predetermined level, and a relief valve 8 isprovided which will open and allow water to escape from the system inthe event that the pressure in the system rises above a predeterminedlevel due to the heating up of the water in the system or 'any othercause.

A strainer 9 is also generally provided for preventing foreign matterfrom entering the heating system. A drain I is also usually providedtoenable Vthe water to be drained from the system when desired. In ourimproved system, we provide in addition to this a valve apparatus ll bymeans of which when desired the pressure in the system, including theradiators, may be dropped below the lower pressure level normallymaintained by the pressure-reducing valve, which drop in pressure inthesystem is utilized in venting the air from air-bound 'radiators throughthe air vent valve mechanism shown in detail in Figs. 4, 5, 6, and 'LBefore describing in further detail the control valve mechanism by meansof which pressure in the system is dropped below the ordinarypredetermined level, we will describe the construction and operation ofthe air vent valve mechanism provided for each individual radiator.

Fig. 4 shows the position of the valves in the air vent apparatus eitherwhen the system is empty or when the water level in the radiator is lowand when the pressure in the system is subnormal.

Fig. shows the position of parts when the water level in the radiator isup to normal and the water pressure in the radiator is below normal.

Fig. 6 shows the position of parts when the waterlevel in the radiatoris normal and the water pressure in the radiator is within the normalrange.

Fig. 7 shows` the position of parts when the water level in the radiatoris below normal (that is to say, when the radiator is air-bound) and thepressure in the radiator is within the normal view showing the with acompression range.

Each radiator is provided with a vent valve apparatus 6; thenipple |l`aof the air vent apparatus being connected so as to be in communicationwith the interior of the radiator so that the liquid level in the airvent apparatus will rise and ,fall with the liquid level in the radiatorand so that the interior of the diaphragm will be subjected to apressure equivalent to the pressure-in the radiator. Assuming that thesystem is empty and the apparatus is therefore in the position shown inFig. 4 and it is desired to flll the system, the control apparatus llwill be set so as to supply water to the heating system. Water willthereupon rise in the different radiators, and when the liquid level ina radiator rises so that the liquid level in the air.vent apparatus ishigh enough to raise the float |2 to the position shown in Fig. 5, thefloat valve |3 will close the passage H in the ported member I 5 carriedby the upper end of the pressure-actuated bellows or diaphragm chamberthe leakage of water from the radiator. When all of the float valves inthe system have thus closed each passage Il, furth r supply of liquidwill increase the pressure in t e system, causing each diaphragm chamberto expand to bring the upper end of the ported member` l5 against theconical valve member l'l as shown in Fig. 6, thus further sealing thepassage I l against the leakage of water. As the area of this diaphragmIG which is acted on by pressure is of a considerable extent, the portedmember l5 will seal against the conical valve member Il withconsiderable force so that'a-secure seal is effected between the portedmember l5 and the conical valve member |1. It will be seen that ifforeign matter is lodged in valve |3 or passage ll, this mighttemporarily prevent the effective closing of the valve but that thegreater power of the diaphragm l6 will force the ported member 14against'the valve ll regardless of the presence of the foreign material.Subsequent operation of the valve and urging of the pressure in thesystem will wash the foreign matter away so that the valve |3 will finda seat and effect a closure. When the pressure in the system has beenbrought up to the predetermined pressure, the control valve apparatus llis set so that any further water supply to the system will be throughthe pressure-reducing valve .1. The radiators have now been filled withwater to the desired level and pressure, and the heating system is readyfor operation.

As previously explained, when water is supplied to the system, air isentrained with the water and in time will rise and accumulate in theupper portions of the radiators causing the radiators to becomeair-bound and causing the float valves l3 to drop to the position shownin Fig. 7 as the liquid level in the radiators falls. In order` to ventthe air-bound radiators, the controlvalve H is placed in a position toconnect the hot Water system with the drain |8, and a small quantity ofliquid is drained from the heating system to lower the pressure in thesystem below that predetermined pressure maintained by thepressure-reducing valve 1 to enable the coil compression spring IS tocompress the diaphragm chamber IG and to move the ported member 15 awayfrom the conical valve member |-1 to the position shown in Fig. 4. Aspreviously explained, Fig.4 shows the position of the valves in the airvent apparatus when the water level in the radiator is subnormal and thepressure in the system is subnormal, which is the condition when theradiator is air-bound and the pressure in the system is low enough toenable the coil compression spring I! to compress the'diaphragm chamberI 6. In this position of parts, the air can escape from the air-boundradiator, as the float valve l3 is open and the pressure-controlledvalve l'l also is open. In explanation of the fact that air will escapefrom the system under these IG, thus preventing anetma conditions, itmust be borne in mind thatthe mixture of water and entrained air in theheating system' expands upon a lowering of the Dres-- sure, due. to-'the elasticity of the entrained air,

and the expansion' of the body of water' and entrained air will causethe air. in the air-'bound radiators to escape whenthe partsare in'theposition shown in Flg.- 4. Thisexpansion of the medium inthe system willcause the liquid level in the float valve chambers to rise andeventually to bring the float valve i3 lto the position shown in Fig.51m which it coses the' port throughthe ported. member 15,- thuspreventing leakage of waterf past. the. float'yalve;A the radiatoi'svhave "all beenvented, whichrequires verylittle time,usuallylessthanz.aminutthecontrolvalve-' il is moved to a position toAprevent'further drainage of the systemv andV to vadd further water tothe system fromfifthev city mam, whereui'ionthev pressure in the systemrises and the diaphragm chambers ISv thereupon expand' to the positionshown in Figi 6;., in' whichV position the 'ported member Vi'5`ispressed firnilyagainsttheV conical valve |1 by the pressure in thediaphragm chamber, thus effectually preventing any leakage through theported member 15. If it should happen that no air is present in some ofthe radiators, the valve .parts will remain as shown in Fig. 5 duringthe period that a subnormal pressure prevails in thesystem.

By means of this control it is a simple matterV to vent all of thevair-boundradiators in a system from a central point so that thisventing can be easily accomplished as often as once a day, or oftener ifnecessary, in order to keep the system in good working condition.

We will now briefiy describe the construction and operation of thecontrol valve mechanism H shown in Figs. l, 2, and 3.

As here shown, the valve casing 20 is provided with four connections,one connection 2| with the water supply, such as the city main 22,another connection 23 for the pipe 24 leading to the pressure-reducingvalve 1, another connec- 'tion 25 for a pipe 26 which by-passes thepressure-reducing valve 1 and the relief valve 3, and another connection21 for the drain 10. This drainage connection |8 may be to the samedrain pipe 28 which leads from the pressure relief valve 8.

The valve casing 20 is provided with a pressure indicator 29 of anysuitable type connected as passage 32 in the valve, and through the'pipe connection 23 to the pipe 24 leading to the reducing valve 1. In'another position o f the valve, the passage 32 through the valveconnects the system with the drain pipe |0 through the vby-pass 26,connection 25, passage 32, passage 33, an'd connection 21. In anotherposition of the valve the passage 32 through the valve connects thewater supply 22 directly with the heating system through the connection2|, passage 32, connection 25, and by-pass 23.

Fig. 2 shows the normal position of the valve 30 in which the supply 22is connected with the pressure-reducing valve 1 so that the pressure inthe system will be kept up at least to the predetermined lower limit forwhich the pressurereducing valve 1.

vin' which the supply pipe '22 is connected with the by-pass pipe 26.the system can be quickly filled-without having to go through thepressure- As one'example of pressures which maybe used-,let 'it beassumed that the reducing valve 1 is setsofthat' the pressure at thegauge 23 will not normally` fall; below ten pounds perV square Vis faten-pound gauge pressure, the. pressure atV the upper endl of theradiator 2. will be seven poundsv per square inch and the pressure atthe upper'end of the radiator 2a will be three pounds per square inch.

` Let .itbe assumed further that the air vent apparatus 6of'the'radiator 2 on thelower floor is set so that the coil compressionspring |9 will cause the ported member |5 to move away from the conicalvalve |1' when the pressure in the upper portion of the radiator 2 dropsbelow `i've and one-half pounds per'square inch, and that the air vent'apparatus of the upper radiator 2a is set so that the coil compressionspring IS will cause the ported member 15 to move away from the conicalvalve |1 when the pressure in the upper portion of the radiator 2a dropsbelow one and one-'half pounds per square inch. Under these conditions,if the radiators are air-bound, they may be vented by dropping thepressure at the pressure gauge down to eight pounds per square inch,which will cause the pressure in the upper portion of the lowerradiator2 to drop down to five pounds per square inch and will cause thepressure in the upper portion of the upper radiator 2a to drop down toone pound per square inch, since these pressures at the radiators offive pounds per square inch and one pound per square inch are less thanthe respective pressures of five and one-half pounds per square inch andone and one-half pounds per square inch at which these air vent valvesopen. As soon as the pressure has been maintained at this low level longenough to vent the radiators, the control valve may be moved back tofilling position which will cut oif further drainage and connect thewater supply with the system to cause the system to be filled up to thepressure which will be sufllcient to expand the diaphragm chambers tocause the ported members to seat against the conical valves. The controlvalve 30 may then be moved back to normal position.

The control valve mechanism ll may be provided with suitable indicia 3|co-operating with a pointer 35 on the valve handle 38 for indicatingthe' position to which the valve handle shall be turned for filling,normal operation, and venting operation. The gauge 29 may be providedwith a scale 31 co-operating with a gauge index 38 showing the pressurein the system, the scaIe 31 having indicia 39 to show the pressure towhich the system should be filled when the valve handle 36 is moved tofilling position, and indicia 40 to show the pressure to which thesystem should be dropped' when venting the radiators.

Referring more specifically to the structure of the air vent apparatus,this comprises a casing 4| for enclosing the float 12 and diaphragmchamber IG, the float itself carrying at its upper end the conical valvemember |3, the corrugated expansible 'diaphragm chamber IS, the portedmember IS secured in fluid-tightengagement with the upper portlon of thediaphragm chamber IB, a guide sleeve 42 for the ported member ISdepending from'the cap 43 of the casing, and a plug 44 from which theconical lvalve memlo ber depends having an adjustable screw-threadedengagement with the sleeve 42 which guides the ported member |5.Thecasing 4| as shown comprises the lower cup-like member .45 whichreceives the lower end of the float 12, a sleeve 15 46 having afluid-tight engagement with this lower cup-like member 45, and the cap43 on which the guide sleeve 42 and plug 44 are mounted. This cap43 isprovided with a suitable opening 41 to enable the escape of air 'which20 flows through the ported member IS. This ported member has a loosefit in the sleeve 42 so that the air can escape between the sleeve 42and the, 'ported member IS. The diaphragm chamber IG may be mounted inany suitable manner as by 25 providing it with a flange 48 secured influidtight engagement with the casing sleeve 46.

It is obvious that if desired the heating system may be provided with apump to force the water therethrough. 30 While we have descrlbed ourinvention in connection with a hot water heating system, it is obviousthat in some of the phases, lt is applicable to a liquid cooling systemor to any system in which a liquid circulates throughout the system 35and in which the system has containers which become air-bound. While wehave shown our invention in connection with a heating system in whichseparate piping is provided for the supply and return with respect tothe radiators, it is 40 obvious that it is also applicable to a hotwater heating system of the single flow type."

In Flg. 8 is shown an arrangement of control for the water in theheating system which may be substituted for that shown in Flg. 1. Inthis 45 arrangement the pipe 48a leading to the heating systemcorresponds to the pipe shown in Fig. 1, and the pipe 22a corresponds tothe supply pipe 22 of Fig. 1. A pressure regulating valve 'I and apressure relief valve 8 are provided correspond- 50 ing to theregulating valve 'l and the relief valve 8 of Fig. 1. A drain connection28a leading from the. pressure relief valve 8 corresponds to the drainconnection 28 of Fig. 1. A by-pass isprovided around the regulatingvalve 'I and relief 55 valve 8 in which .is located the control valvemechanism. This control valve mechanism comprises a casing 20a havingthree connections, one connection 2 la for the pipe 22a leading from thewater supply. another connection 25a for the pipe 50 48a leading to theheating system, and another connection 2'la`for the pipe leading to thedrain. This valve mechanism is also provided with an indicator 29asimilar to the indicator 29 shown in Fig. 3. In the position of thevalve shown, both 65 the connection 25a and the connection 21a are cutoff from the supply pipe- 22a. If the plug valve is turned 90 clockwise,the supply pipe 22a will be connected With the pipe 48a leading to theheating' system, by-passing the pressure- 70 regulating valve 1. If theplug valve is turned 45 counterclockwise, the heating system will beconnected with the drainage connection 21a. In thisl construction, as inthe construction of Fig. 2, the gauge is provided with indiciaco-operating 75 with the pointer 38a to show the pressure in the system.The indicia '39a show when the system has been. illled to the properpressure, and the indicia 40a show when the system has been vented to an:extent sulciently to cause the collapse of lthe expansible lbellows IBto' open the valve l'l and vent the radiators.

The construction shown in Flg. shows a vent valve mechanism in which theopening of the air `vent valve is effected by an increase in thepressure in the radiator to supernormal as distin- 10 guished from theconstruction shown in Figs. 4 to 7, inclusive, in which the opening ofthe air vent is eifected by a drop in. the pressure vto subnormal. Theconstruction shown in Flg. 10 comprises a float I 2' and a float valve|3' similar to the fioat |2 and fioat valve II of Flg. 4, a casingcomprising a cup member 45a having a nipple l la similar to the cupmember 45 and nipple Ila of Flg. 4, an expansible diaphragm or bellows49 carrying a valve member 50 at its lower end, a spring 5| urging thevalve 50 to closed position, a ported member 52'having a passage 53therethrough controlled both .by the fioat valve |3' and. thespring-pressed valve 50, a plate 54 bearing against the upper end 'ofthe spring 5|, and an adjusting screw 55 for adjusting the tension ofthe spring 5|. The ported member 52 is secured to a partition 56 securedto a sleeve 51 forming part of the casing. The casing comprises, inaddition to the sleeve 51, an upper sleeve 58 having a screw-threadedconnection with the sleeve 51, and a cap 59 having a screw-threadedconnection with the sleeve 58. The sleeve 58 ls provided with a suitablevent 60 for the escape of air.

In this form the bellows 49 acts merely as a mounting for the valve. 50and as a housing for the spring 5|. The interior of the diaphragm is notsubjected to the pressure of 'the system as in the construction of Fig.4.

.In a sealed pressure hot water system, the operation of the valveshownin Fig. 10 .will be as follows: Let it be assumed that the relief valve8 is set to open at a pressure of thirty pounds per square inch.'thusestablishing an upper limit for 'the normal pressure range. Under thiscondition the screw Elwill be adjusted to control the tension of thespring 5| in such a manner that the pressure in the system acting on theexposed surface of the valve will open this 50 valve at a pressuresomewhat higher than the pressure at which the relief valve is set toopen; for instance, at a pressure of thirty-flve pounds per square inch.When it is desired to vent the radiators, the pressure in the systemwill be increased to thirty-flve pounds per square inch or slightlyabove that. This may be accomplished byV any one of thefollowingmethods: (1) closing thedischar'ge from the relief valve untilthe de- .sired supernormal'v pressure has been attained and held for. ashort'time; (2) closing the connection to the relief valve until thedesired supernormal pressure has been attained and held for a short`time; (3) opening a by-pass connection from the water supply into thesystem until the desired supernormal pressure has been attained and heldfor a short time; and (4) opening a connection from the water supply tothe heating system and closing the discharge from, or the connection to,the relief valve until the desired supernormal pressure has beenaccomplished and held for a short time. All of these may be accomplishedby an arrangement similar to that shown in Figs. 8 and 9. Under any oflthe four conditions, if any air has been accumulated in a radiator, thefioat valve will be open, the supernormal pressure will open thespring-pressed valve I.,

and the air will be discharged. The water will rise in the float valvechambencausing the li'ioat valve to close. The pressure will then bepermitted to drop back to the normal pressure at which the reliefvalveopens' and thereupon thevalve will close.

If it is desired to use the valv'e mechanism 'shown in Fig. 10 in anopen gravity hot water sary to close the overflowrtemporrily, whereuponvthe pressure in thesystemv can be'increased to something more than tenpounds per square inch, causing the pressure-opcrated 'valves ,50 toopen and allow the venting lof any radiators which are airbound. As theWater rises in the radiator, the

iioat valve |3 will close and when all the radiatorsv have beenvented-the pressure is allowed to drop;

back to normal whereupon the' valves 501 lwill close and the system canthen operate'in a normal manner.

In Fig. 11 is shown diagrammatically an automatic time-controlled valvemechanism which can be substituted for the control valve mechanism shownin Figs. 8 and 9. In Fig. 11 the connection 25h corresponds vto theconnection 25a of Fig. 9, the connection 2lb corresponds to connection2|a of Fig. 9, and the connection 2117 corresponds to connection 21a ofFig. 9. The connection 2ib will be placed in communication with thesupply pipe 22a, the connection 25b will be placed in connection withthe pipe 48a, and the connection 21h will be connected with the drainpipe 28a.

The construction shown in Fig. 11 co'mprlses the valve casing having theabove-noted pipe connections 2|b, 25h, and 21h. a valve 6| controllingthe port 62 leading to the connection 21h, a valve 63 controllingcommunication between the connections 2| b and 25D. solenoids 64 and 65for controlling these valves 6| and 63, respectively, springs 64a and65a for closing the valves 6| and 63, respectively, when the solenoidsare deenergized, a time-controlled program cycle apparatus 66 of anysuitable type controlling the solenoids and a time-controlled mechanism61 controlling the program cycle mechanism 66. The time-controlledprogram cycle mechanism 66 may be controlled by the.

primary time-controlled mechanism 61 in such a manner that at a certaintime or certain times during the period covered by the primarv mechanism61, the program cycle mechanism 66 will be caused to make one completerevolution in a relatively short period, for example, in a minute orthereabouts. This complete revolution of the program cycle mechanismwill cause the energization and deenergization of both solenoid magnets64 and 61, which in tum will cause opening and closing of the solenoidcontrolled valves 6| and 63. The program cyclemechanism 66 may be sodesigned that the valve 6| will be opened and held open for a shortperiod, say twenty or twenty-five seconds, long enough to lower thepressure in the system sufliciently to cause venting of the air-boundradiators in the system and so that thereafter the valve 63 will beopened .and held open for a short period, for

example, twenty or twenty-nve seconds, long enough to fill thesystemagain to the desired pressure.

In hot water systems, it may sometimes be desirable to install ventingapparatusonV the pipes leading to the radiatorsV sothat' some of. theair entrained' in the systemcan be vented' before it'reaches theradiators. g

It is obvious that, if desired,' two manually operated switches may beprovided in addition to the time-controlled mechanism shown in Fig. 11for controlling the action of the solenoids 64 and 65 so that i-f thetime-controlled mechanism should fall or if it should be desired toventthe radiators at some Vtime other' than the time-con! trolledperlod;this could'bc'd'one by Operating the manually-operated switches.

vFig,12- shows' an' arrangement in control valve mechanism shown inFigs. 8 and 9 may be combinedv with lacompressed air: tank J which the'68 which is in'communication. with the. piping j 3' leading to theradiators. This compressed. air tank is connected` with the 'piping 3.bymeans Iof" the-'pipe.'69.' 'As the pressure in the'pipev 3' rises and'falis, the air in the tank-68 will be comypressed lor expanded inaccordance with the existing pressure. By c'onnecting the control valvemechanism 20a of Fig. 9 with the compressed air tank 68, as indicated inFig'. 12, the venting of the radiators can be controlled'by manipulationof the valve handle 36. In 'this arrangement, the' connection 25a, ofthe valve 20a. will be connected with the compressed air tank 68 bymeans of the pipe 10, the connection 2|a of the valve will be connectedwith any suitable source of compressed air 1|, and the connection 21awill be connected with any suitable air exhaust pipe. With thisarrangement, the air-bound radiators maybe vented by placing the valvein position to establish communication between the connection 25a andthe connection 21a; This will allow the air to escape from thecompression tank 68 through-the exhaust 21a, lowering the pressure inthe system and causing the venting of air-bound radiators as previouslydescribed. After the radiators have been vented, thepressure in thesystem may be restored to normal by moving the valve to connect thecompressed air source 1| with the pipe 10 leading to the comi pressiontank 68. The valve will be held in this prior art and the scope of theappended'claims. v

Having thus described our. invention, what we claim and desire to secureby Letters Patent is:

1. A liquid heat 'transfer system comprising a source of liquid underpressure, a heat transfer liquid container in communication with saidsource, means for supplying heat to said system, and means forcontrolling the venting of air from the container when Vit becomes. airbound comprising means controlled by aA change of pressure of the liquidin the container and by a change in liquidlevelfin the container, andautomatic means for changing the pressure in the container independentlyof any heat supply control.

2.`A liquid heat transfer system comprising a source of liquid underlpressure, a heat transfer liquid container in communication with saidsource, means for supplying heat to said system, and means forcontrolling the venting of air from the container when it becomes airbound comprising means Controlled by a change of pressure of the liquidintthe container and by a change in liquid level in the container, andtime-controlled means for changing the pressure in the containerindependently of any heat supply control. i

3. A liquid heat transfer system comprising a source of heat transferliquid under pressure, a liquid container in communication with saidsource, means for supplying heat to said system; and means for ventingthe air from the container when it' becomes air bound comprising meansactuated by a change in pressure of the heat transfer liquid in thecontainer, and timecontrolled means for changing the pressure in' the`container independently of any heat supply control.

4. Apparatus for controlling the venting of air from an air-bound heattransfer liquid container, said apparatus having a passage for theescape of air from the container, two valves in series in said passage,means controlled by the pressure of the liquid in the container forcontrolling one of said valves, means controlled by the liquid level inthe container for controlling the other valve, and time-controlled meansfor changingl the pressure in the container independently of any heatsupply control. r

5. A liquid heat transfer system comprising a source 'of heat transferliquid under pressure, means for supplying heat to said system, a liquidcontainer in communication with said source, and means for venting theair from the container when it becomes air bound comprising meansactuated by a change in pressure of the heat transfer liquid in thecontainer, and automatic means for changing the pressure in thecontainer independently of any heat supply control.

6. Apparatus for controlling the venting of air from an air-bound heattransfer liquid container, said apparatus having a passage for theescape of air from the container, two valves in series in said passage,means controlled by the pressure of the liquid in the container forcontrolling' one of said valves, means controlled by the liquid level inthe container for controlling the .other valve, and automatic means forchanging the pressure in the container independentlyl of any heat supplycontrol.

7. A heat transfer system comprising a source of heat transfer fluid,means for transferring heat with respect to said fluid, a heat transfercontainer having an air vent, means for maintaining the pressure of saidfluid in said container within a normal range for efi'ecting heattransfer, and means actuated by a fluid pressure outside of said rangeand independently of the action of said heat transferring means forventing the air trapped in said container.

8. A heat transfer system comprising a source of heat transfer liquid, aheat transfer container having an air vent, means for supplying liquidto said container, means for maintaining the pressure of said heattransfer liquid in said container within a normal range for effectingheat transfer, means for temporarily changing the liquid pressure at apressure outside said sure outside of said range for venting the airtrapped in'said container, and means controlled by the rise of theliquid level in said container for causing said pressure-controlledmeans to close said air vent. i

9. A heat transfer system comprisinga source of heat transfer liquid, aheatv transfer container having an air vent, means for supplying liquidto said container, means for maintaining the pressureof said heattransfer liquid in said container within a normal range for effectingheat transfer, 'means for temporarily changing the liquid pressure at apressure outside said normal range, means controlled by a liquidpressure outside of said range for venting the air trapped in saidcontainer, and means controlled by a rise in liquid level in thecontainer for preventing the flow of air through said vent.

10. A heat transfer system comprising a source of heat transfer fluid,means for transferring heat with respect to said fluid, a plurality ofheat transfer containers. each having an air vent,

means for maintaining the pressure of said fluid in said containerswithin a Vnormal range for effecting heat transfer, and means actuatedby a fluid pressure, outside of said range and indenormalrange, meanscontrolled by a liquid prespendently of the action of said heattransferring means for venting the air trapped in said con- -tainers.

11. A heat transfer system comprising a source of heat transfer liquid,a plurality of heat transfer containers, each having an air vent, meansfor supplying liquid to said container, means for maintaining thepressure of said heat transfer liquid in said containers within a normalrange for effecting heat transfer, means for temporarily changing ,theliquid pressure at a pressure outside said normal range. meanscontrolled by a liquid pressure outside of said range for ventingthe'air trapped in said containers, and means controlled by the -rise ofthe liquid level in said containers for causing said pressure-controlledmeans to close said air vents.

'12. A heat transfer system comprising a source of heat transfer fluld,a heat transfer container having an air vent, means for transferringheat with respect to said fluid, means for maintainingthe pressure ofsaid fluid in said container within a normal range for effecting heattransfer, means for temporarily changing the fluid pressure to apressure outside of said normal range, and means controlled by saidfiuid presand for opening the vent when the pressure is outside thenormal range.

13. A heat transfer system comprising a source of heat transfer liquid,a heat transfer container having an air vent. means for supplying liquidto said container, means for maintaining the pressure of said heattransfer liquid in said container within a normal range for effectingheat transfer, means for temporarily changing the liquid' pressure to apressure outside of said normal range, and means controlled by saidliquid pressure for closing the vent when the pressure is within thenormal range and for opening the vent when the pressure is outside thenormal range.

14. A heat transfer system comprising a source of heat transfer liquid,a heat transfer container having an air vent, means for maintaining theaaa-1,920

said vent closed at pressures within said normal range.A t

15. A heat transfer system comprising a source' of heat transfer liquid,a heat transfer container having an air vent, means for maintaining thepressure of said heat transfer liquid in said container within a normalrange for effecting heat transfer, means for temporarily changing theliquid pressure to a pressure outside of said normal range, means insaid system controlled by the liquid level, means in said systemcontrolled by the liquid pressure, and means controlled by said liquidlevel controlled means and by said liquid pressure controlled means forventing said container at coincident low liquid level and pressureoutside said normal range and for closing said vent alt high liquidlevels and at pressures within said normal range.

16. A heat transfer Vsystem comprising a source of heat transfer liquid,a heat transfer container having an air vent, means for maintaining thepressure of said heat transfer liquid in said container within a normalrange for effecting heat transfer, means for temporarily changing thefluid pressure to a pressure outside of said normal range, meanscontrolled by said fiuid pressure for closing the vent when the pressureis within the normal range and for' opening the vent when the pressureis outside the normal range, and means controlled by a rise in liquidlevel in the container for preventing the flow of air through said vent.

17. An air vent control device comprising pressure expansiblechamber'means, a ported valve seat carried thereby for venting airthrough said chamber, a valve member cooperating with said seat to closethe port by the pressure controlled movement of the chambe and a floatvalve for controlling the flow of air through said port.

18. An air vent control device comprising pressure expansible chambermeans, a ported valve seat carried thereby for venting air through saidchamber, a valve member co-operating with said seat to close the port bythe pressure controlled movement of the chamber, and a valve-carryingiloat for controlling the passage of air through said port.

19. An air vent control device eomprising pressure expansiblo chambermeans, a ported valve seat carried thereby for venting air through saidchamber, a valve member oo-operating with saidv seat to close the portby the pressure controlled'movement of the chamber, and a valve- 5carrying float for controlling the passage of air through said port,said float having a portion lying in said expansible chamber.

20. Thecombination of a liquid filled heat transfer system and means forventing the system at several points simultaneously from a single point,said means comprising a pressure controlling member designed to changethe internal pressures of the system -to exceed the normal range ofinternal pressures, and a ported member at each of the points to bevented controlled by liquid pressure and liquid level, said portedmembers being designed to close when the internal pressures are `,withinthe normal rangeand to lbeopened when the internal pressures of thesystem exceed the normal range, said ported members being v`designed toclose with the rise of liquid level.

21. A liquid fllled heating system comprising a means for heating theliquid, heat transfer units, connections therebetween, means formaintaining the internal pressure of the system within a predeterminedrange, means for changing said-pressure range independently of saidheating means, a container at each of the several units to be ventedcommimicating with the interior ofsaid units, a port in each containercommunicating with the atmosphere, a pressure responsive member withineach container, a valve member actuated by each said pressure responsivemember cooperating to close each said port when the intemal pressure ofthe system is within the predetermined range, .and a float actuatedvalve member cooperating to close each of said ports to the passage ofliquid. 40

22. A remotely operated leak-proof vent valve for venting the'air fromair-bound hot water radiators comprising a chamber. the lower end ofwhich is designed to be brought into communication with the interior-`of the radiator. the upper end of the chamber having a portcommunicating with .the outer atmosphere, a noat valve designed to ciothe port to the passage of water, a second valve member, a pressureresponsive member cooperating there'with 50 forcibly to close the portby the normal internal pressuresofthesystem.saidpressureresponsivemember being adjustably set to open the portwhenthepressurewithinthesystemisbelow normal, an'd meam for.reducing theinternal pressures to below the normal range independently of any firecontrol. i

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